Electrically conductive helically fabricated flexible hose in common use for vacuum cleaners and other purposes is constructed of one or more open-turn helices of insulated wire covered with a convoluted flexible plastic wall. The wires serve not only as a structural support for the hose wall but also as circuit means for carrying electlrical current from one end of the hose to the other. Product quality control standards require that each length of such hose be tested to insure the dielectric integrity of the insulation around the conductor.
The convoluted exterior of hose of this kind has presented a problem in test procedure. Heretofore the accepted practice has been to wrap each length of hose with aluminum foil conforming closing to the irregular shape of the hose and then to apply a voltage between the conductor of the hose and the foil. Any leakage of current indicates a failure of the dielectric integrity of the sample and it is rejected. It is an extremely time consuming matter to wrap and unwrap each hose in this procedure and of course the foil must be frequently replaced.
The present invention has as its principal object the provision of apparatus and a method for carrying out such tests rapidly, accurately and easily with no use of consumable materials such as foil.